Abstract

This study aims to compare skin perfusion pressure measurements (SPP) at midfoot and below knee level performed with a novel laser Doppler flowmetry (LD) probe with a reference method based on photo plethysmography (PP). It includes 40 patients referred with known or suspected peripheral arterial disease. The SPP was performed with both devices. Blinded re-interpretation of the SPP measurements was carried out by three observers and a consensus quality score was provided for each measurement. SPP >40 mmHg was considered a clinically relevant cut-off. This study evaluates a total of 48 paired measurements of the midfoot and 54 below knee. The two methods agreed in overall diagnostic classification in 80 of 102 measurements (78%) with both methods showing SPP ≥40 mmHg in 21 cases, and both methods showing SPP <40 mmHg in 59 cases. Of the 22 participants with disagreement (22%) in overall classification, 15 had measurements within the range of 30-50 mmHg, and 7 with a clinically relevant disagreement with one device showing SPP <30 mmHg and the other ≥40 mmHg. Analysis of inter observer variation for the LD readings showed an intraclass correlation coefficient of 0.880 (95% CI: 0.807 to 0.929, p- value <0.05) at midfoot, and 0.933 (95% CI: 0.894 to 0.959, p-value <0.05) at below knee level. The novel probe based on LD showed good correlation with PP in absolute pressures, sufficient agreement in overall disease classification as well as good to excellent reliability in terms of inter observer variation.

摘要

本研究旨在比较使用新型激光多普勒血流仪 (LD) 探头在足中部和膝下水平的皮肤灌注压测量 (SPP) 与基于光体积描记法 (PP) 的参考方法。它包括 40 名已知或疑似外周动脉疾病的患者。SPP 是用两种设备进行的。由三名观察员对 SPP 测量进行盲法重新解释，并为每次测量提供一致的质量评分。SPP > 40 mmHg 被认为是临床相关的临界值。这项研究评估了总共 48 对中足和 54 对膝下的测量。这两种方法在 102 次测量中的 80 次（78%）的总体诊断分类一致，两种方法均显示 SPP ≥40 mmHg 21 例，两种方法显示 SPP <40 mmHg 59 例。在 22 名总体分类存在分歧 (22%) 的参与者中，15 人的测量值在 30-50 mmHg 范围内，7 人与一个显示 SPP <30 mmHg 和另一个 ≥40 mmHg 的设备存在临床相关分歧。对 LD 读数的观察者间变异分析显示，足中部的组内相关系数为 0.880（95% CI：0.807 至 0.929，p 值 <0.05）和 0.933（95% CI：0.894 至 0.959，p值 <0.05) 在膝盖以下。基于 LD 的新型探针在绝对压力方面与 PP 具有良好的相关性，在整体疾病分类方面具有足够的一致性，并且在观察者间的变异方面具有良好的可靠性。